The present invention relates to a production planning method for planning the production of products, such as semiconductor devices, requiring a relatively longer cycle time of production and advance processing based on a predictive demand, a storage medium and a production planning apparatus.
Many techniques have been known for managing the production process.
For example, JPN PAT APPLN KOKAI PUBLICATION Nos. 64-34644 and 6-328351 have proposed the technique for controlling the quantity of production of finished products at a ratio of productions among the kinds of items.
JPN PAT APPLN KOKAI PUBLICATION No. 3-14675 has proposed an in-process vehicle management method for grasping the number of stocks (vehicles) in the process on a per-specification basis and controlling a total quantity of works per kind.
Further, "An adjustment Method for Balanced Production Scheduling Problem" in "Proceedings of Production Scheduling Symposium '95" (Oct. 2, 1995 Kyoto)--pp 187 to 192--has proposed The Institute of System's Control & Information Engineers discloses the technique of balancing a daily quantity of processing in respective processes.
JPN PAT APPLN KOKAI PUBLICATION No. 8-252749 discloses a balancing system in production planning, that is, a production planning system for, as a basic policy, balancing a quantity of production in unit interval.
As set out above, a planning system is known for, as a goal, balancing a quantity of processing or a quantity of production in unit cycle time in production planning, that is, inputting a target production in planning cycle time and a work allocation at a planned time and finding a quantity of processing required in the planning cycle time. Further, also known is a method for controlling a total quantity of works on a per-kind basis.
In the conventional method, when the number of loads in the respective equipment derived from the target production, that is, the number of works to be processed up to a delivery in respective equipment, exceeds the processing capability, then the exceeded load quantity is reduced by a stacking/leveling method. However, this method can simply draw up a micro-production plan in lot units.
For a product, such as a semiconductor device, involving an ever decreasing tendency in the cycle time of processing from the ordering to the delivery, an advance production is carried out, prior to the actual ordering, based on a predictive demand. For such a micro-production planning in lot units, however, the production adjustment cannot be achieved smoothly.